Who was the last British monarch to accede to the throne at the death of someone other than a sibling or parent?

The last British monarch to accede to the throne at the death of someone other than a sibling or parent was Queen Anne, who became queen in 1702 following the death of her brother-in-law, King William III. Anne was the daughter of James II and became monarch after the Glorious Revolution, which resulted in the exclusion of her father from the throne. She ruled until her death in 1714, after which the throne passed to her second cousin, George I.